Effect of pubertal development and physical activity on plasma ghrelin concentration in boys

The aim of the present study is to assess the influence of physical activity on a new hormone , ghrelin, who is involved in many physiological as well psychological processes

Light and electron microscopial immunolocalization of neurpeptide Y-containing nerves in the hamster gallbladder

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Relationships between ghrelin concentrations and metabolic parameters in boys

The aim of the present study was to assess the influence of regular physical activity on ghrelin concentration and the interrelationships between ghrelin and metabolic and biochemical parameters in boys. In total, 56 healthy schoolboys aged between 10 and 16 years were divided into the swimming (n = 28) and the control (n=28) groups. The subjects were matched by age and body mass index (BMI), generating 9 matches pairs in pubertal group I (Tanner stage I), 11 pairs in group II (pubertal stages 2 and 3) and 8 pairs in group III (pubertal stages 4 and 5). Plasma ghrelin levels were significantly higher in the swimmers group II and II than controls (group II: 1126.8+- 406 vs 803.3+-411,2 pg/ml; group III: 1105.5+-337.5 vs 850.8+-306 pg/ml). Ghrelin was significantly correlated with VO2peak in control group ( r = -0.530; p < 0.05), while not in the swimmwrs group. From biochemical parameters ghrelin was significantly related to testosterone ( r = - 0.596), IGF-1 ( r = - 0.656) and IGFBP-3 ( r = -0.494). No relationships were observed in the swimmers group between ghrelin and biochemical parameters. In conclusion, ghrelin concentration decreased during puberty in physically inactive boys

The impact of ghrelin on bone mineral density in boys : effect of biological maturation and physical activity

The aims of the present study were to: 1) assess the influence of regular phsyical activity on ghrelin concentration in prepubertal and pubertal boys; and 2) examine the impact of ghrelin and insulin like growth factor-I (IGF-I) concentrations on bene mineral density (BMD) in boys with different physical activity patterns at different pubertal stages. In total, 56 healthy schoolboys aged between 10 and 16 years were divided into the swimming (n=28) and the control (n=28) groups. The subjects were matched by age and body mass index (BMI) genrating 9 matches pairs in pubertal group I (Tanner stage 1), 11 pairs in group II (pubertal stages 2 & 3) and 8 pairs in group III (pubertal stages 4 & 5). To reduce the effect of body size on BMD vaues, apparent volumetric bone mineral density (BMAD) of the lumbar spine was calculated. Swimers in pubertal groups IIand III had significantly (both p < 0.05) higher mean plaslma ghrelin concentration than the control groups. In conclusion plasma ghrelin concentrations decreased durign puberty in physically inactive boys, while in regularly physically active boys it remained relatevely unchanged

The role of exercise intensity in the bone metabolic response to an acute bout of weight-bearing exercise

We compared the effects of exercise intensity (EI) on bone metabolism during and for 4 days after acute, weight-bearing endurance exercise. Ten males [mean ± SD maximum oxygen uptake (Vo(2max)): 56.2 ± 8.1 ml·min(-1)·kg(-1)] completed three counterbalanced 8-day trials. Following three control days, on day 4, subjects completed 60 min of running at 55%, 65%, and 75% Vo(2max). Markers of bone resorption [COOH-terminal telopeptide region of collagen type 1 (β-CTX)] and formation [NH(2)-terminal propeptides of procollagen type 1 (P1NP), osteocalcin (OC), bone-alkaline phosphatase (ALP)], osteoprotegerin (OPG), parathyroid hormone (PTH), albumin-adjusted calcium (ACa), phosphate (PO(4)), and cortisol were measured during and for 3 h after exercise and on four follow-up days (FU1-FU4). At 75% Vo(2max), β-CTX was not significantly increased from baseline by exercise but was higher compared with 55% (17-19%,

Dose-dependent relationship between severity of pediatric obesity and blunting of the growth hormone response to exercise

In children, exercise modulates systemic anabolism, muscle growth, and overall physiological development through the growth hormone (GH)-insulin-like growth factor I (IGF-I) axis. GH secretion, at rest and during exercise, changes with age and maturational status and can be blunted by hyperlipidemia and obesity, with possible negative effects on physiological growth. However, little is known about the effect of progressively more severe pediatric obesity on the GH response to exercise and its relationship to pubertal status. We therefore studied 48 early- or late-pubertal obese children [body mass index (BMI) >95th percentile, separated in tertiles with progressively greater BMI] and 42 matched controls (BMI <85th percentile), who performed ten 2-min cycling bouts at ∼80% of maximal O2 consumption, separated by 1-min rest intervals. Plasma GH and IGF-I were measured at baseline and end exercise. GH responses were systematically blunted in obese children, with more pronounced blunting paralleling increasing BMI. Although overall the GH response to exercise was greater in late-pubertal than in younger children, this blunting pattern was observed in early- and late-pubertal children. Our results reveal insight into the interaction between pediatric obesity and key modulators of physiological growth and development and underscore the necessity of optimizing physical activity strategies for specific pediatric dysmetabolic conditions